The present invention generally relates to toilet apparatus and, in a preferred embodiment thereof, more particularly relates to flushing systems for tank type toilets.
Conventional toilets for residential use typically include a bowl having a bottom outlet opening, a trapway communicating with the bottom outlet opening and forming therewith a flushing discharge passage from the bowl, and a water holding tank positioned behind and adjacent the bowl. In the "low tank one piece" version of the toilet, the tank is formed integrally with the bowl and has a top side positioned only a relatively short distance higher than the top side of the bowl. In the "high tank two piece" version of the toilet, the tank is formed separately from the bowl and has a top side considerably higher than its low tank counterpart.
In toilets of conventional low tank, one piece construction and operation, flushing of the toilet is typically initiated by rotating and then releasing a handle externally mounted on the tank to, in turn, upwardly rotate and then release a trip lever disposed within the tank and connected by a chain to a flapper member covering and sealing an open inlet seat portion of a flushing passageway routed from the interior of the tank to the interior of the bowl. Rotation and release of the trip lever momentarily raises the flapper member from the flushing passageway inlet seat, thereby permitting a quantity of tank water to flow through the passageway into a lower portion of the bowl to create a bowl flushing action therein.
At the same time that the tank water is flowing into the bowl via the flushing passageway, a float within the tank begins to drop as flushing water exits the tank. The downward movement of the float opens a ballcock valve within the tank which, via a diverter valve and a conduit structure connected thereto, permits pressurized water from an external source thereof to flow into the bowl to create therein a rim flushing action that supplements the bowl flushing action generated by tank water entering the bowl at the same time.
The entry of the bowl flushing and rim flushing water into the bowl rapidly raises the bowl and trapway water levels, thereby creating a trapway siphoning action that flushes water from the bowl. When the water level in the tank downwardly reaches a predetermined level, the diverter valve reroutes the pressurized water supplied thereto via the ballcock valve to refill the tank and the bowl. As the tank is filled, its internal float rises until it shuts off the ballcock valve, thereby readying the toilet for a subsequent flush.
Although residential toilets of this general type previously required about 3.5 gallons of water for each flush, recent federal regulations have reduced the permissible per flush water amount to 1.6 gallons. The need to meet this criteria led to substantial redesigns of tank type toilets and their flushing mechanisms. However, for a variety of reasons, none of these redesigned toilets and associated flushing mechanisms have proven to be entirely satisfactory.
For example, in conjunction with a low tank, one piece toilet, one proposed design for creating a suitably efficient flush using only 1.6 gallons of water has been to reduce the toilet bowl trapway diameter, and install a specially designed inner pressurized water holding flush tank within the larger main flush tank portion of the toilet. After the toilet is flushed, this internal tank is filled with inflowing supply water, via a pressure reduction valve, in a manner such that when the internal tank is filled the water therein is pressurized by a quantity of pressurized air trapped in the internal tank. When the toilet is flushed, 1.6 gallons of pressurized water is forcefully injected into the bowl, the air pressurized water cooperating with the reduced diameter trapway to effect flushing with the mandated reduced volume of water. The use of this pressurized flushing tank concept, despite its effectiveness at reducing flushing water usage, has the decided disadvantages of being noisy and relatively expensive to incorporate into a toilet.
Another approach used to modify a low tank, one piece toilet is to place an electric motor-driven impeller mechanism into the trapway and cause the impeller to forcefully drive the 1.6 gallons of water rapidly through the trapway, in response to the initiation of a flushing cycle, thereby improving the flushing efficiency of the sharply reduced quantity of water discharged from the bowl. This technique has the disadvantages of being complex, requiring an electrical system to be associated with the toilet, and adding considerable cost to the overall cost of the toilet.
A somewhat different approach has been proposed for use in conjunction with a high tank, two piece toilet. In this type of toilet, as in the case of its low tank one piece counterpart, the cross-sectional area of the trapway is substantially reduced. Additionally, the larger tank water head available in the high tank toilet is used to create a gravity-created flushing jet originating on the front interior side of the bowl and directed at the trapway entrance opening.
This approach also has several disadvantages. For example, the need to have the main flushing discharge opening at the front side of the bowl increases casting complexity and cost. Additionally, because gravity-created flushing jet is not as powerful as the flushing jet emanating from the previously described internally pressurized tank, the wash-down performance of this flushing technique tends to be marginal, and the smaller trapway is more prone to clogging.
From the foregoing it can readily be seen that a need exists for a tank type toilet having improved flushing apparatus and methods that operate with a per flush water quantity of 1.6 gallons and eliminate, or at least substantially reduce, the above-mentioned problems, limitations and disadvantages commonly associated with tank type toilets having conventional lowered water quantity flushing systems. It is accordingly an object of the present invention to provide such an improved tank type toilet.